Coulometric measurement of the porosity in thin nickel coatings

An electrochemical method has been developed to test the porosity in Ni coatings deposited on a CuSn6 substrate. The number of coulombs measured during an anodic potentiodynamic polarization of coated samples in a Na sub 2 SO sub 4 exp + Rochelle salt solution is associated with the area of uncoated substrate material. This provides an index of the coating porosity, based on which the porosity can be assessed and compared quantitatively, for coatings produced under different plating conditions related, e.g. to substrate conditions and coating thickness. Graphs, Photomicrographs. 15 ref.--AA